Encapsulated payloads bonded to polymeric materials

ABSTRACT

In an example, a polymeric material includes a fibrous substrate, a cyclic compound chemically bonded to the fibrous substrate, and a microcapsule. The microcapsule has an encapsulated payload and is reversibly bonded to the fibrous substrate via the cyclic compound.

I. CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application and claims priority fromU.S. patent application Ser. No. 14/693,027, entitled “ENCAPSULATEDPAYLOADS BONDED TO POLYMERIC MATERIALS,” filed on Apr. 22, 2015, whichis incorporated herein in its entirety.

II. FIELD OF THE DISCLOSURE

The present disclosure relates generally to encapsulated payloads bondedto polymeric materials.

III. BACKGROUND

Microcapsules may be used as release systems for various types ofmaterials (also referred to as “payloads”). Examples of payloads mayinclude perfume oils, repellants, self-healing agents, or disinfectingagents, among other alternatives. Rupturing the microcapsule, andrelease of the payload, may depend on mechanically breaking a polymershell of the microcapsule. For example, the polymer shell may be brokenby scratching, puncturing, or other mechanical means directly applied toa polymeric surface of the microcapsule. When the microcapsule iscoupled to a polymer such as a fiber, it may be difficult to break thepolymer shell via direct application of mechanical force. Further, theremay be challenges associated with adhering the microcapsules to thepolymer, such as the fiber.

IV. SUMMARY OF THE DISCLOSURE

According to an embodiment, a process for bonding a microcapsule havingan encapsulated payload to a polymeric material is disclosed. Theprocess includes applying a microcapsule (having an encapsulatedpayload) that includes a dienophile functional group to a polymericmaterial that includes a diene functional group. The process furtherincludes bonding the microcapsule (having the encapsulated payload) tothe polymeric material via a chemical reaction of the dienophilefunctional group with the diene functional group.

According to another embodiment, a process of modifying a firstpolymeric material to form a second polymeric material is disclosed. Theprocess includes de-bonding a first microcapsule that is reversiblybonded to a polymeric substrate of a first polymeric material to form adiene-functionalized polymeric substrate. The process includes applyinga second microcapsule having an encapsulated payload to thediene-functionalized polymeric substrate. The second microcapsuleincludes a dienophile functional group. The process further includesforming a second polymeric material by bonding the second microcapsule(having the encapsulated payload) to the polymeric substrate via achemical reaction of the dienophile functional group with a dienefunctional group of the diene-functionalized polymeric substrate.

According to another embodiment, a polymeric material is disclosed. Thepolymeric material includes a fibrous substrate, a cyclic compound, anda microcapsule having an encapsulated payload. The cyclic compound ischemically bonded to the fibrous substrate, and the microcapsule (havingthe encapsulated payload) is reversibly bonded to the fibrous substratevia the cyclic compound.

One advantage of the present disclosure is the ability to improveadhesion of a microcapsule (having an encapsulated payload) to apolymeric material, such as natural fibers (e.g., cotton fibers) and/orsynthetic fibers (e.g., polyester fibers). A microcapsule (having anencapsulated payload) may be functionalized to include a dienophilefunctional group (e.g., during synthesis of the microcapsule). Apolymeric material may be functionalized to include a diene functionalgroup for chemical reaction with the dienophile functional group. Achemical reaction of the dienophile functional group with the dienefunctional group results in the microcapsule (having the encapsulatedpayload) being bonded to the polymeric material.

Another advantage of the present disclosure is the ability to de-bond(e.g., via a retro Diels-Alder reaction) a first microcapsule that isreversibly bonded to a polymeric substrate of a first polymericmaterial. After de-bonding the first microcapsule, a second microcapsulemay be chemically bonded to the polymeric substrate to form a secondpolymeric material. As an example, the first microcapsule may have afirst encapsulated payload, and the second microcapsule may have asecond encapsulated payload. In some cases, the second encapsulatedpayload may be the same as the first encapsulated payload in order toreplenish a payload material (or multiple payload materials) that may bereleased as a result of a microcapsule being ruptured. In other cases,the second encapsulated payload may be a different payload in order toprovide alternative and/or additional functionality.

Features and other benefits that characterize embodiments are set forthin the claims annexed hereto and forming a further part hereof. However,for a better understanding of the embodiments, and of the advantages andobjectives attained through their use, reference should be made to theDrawings and to the accompanying descriptive matter.

V. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a chemical reaction diagram showing the preparation of apolymeric material with a microcapsule (having an encapsulated payload)that is (reversibly) bonded to a polymeric substrate, according to oneembodiment;

FIG. 2 is a chemical reaction diagram showing the preparation of adienophile-functionalized alcohol for use in preparation of adienophile-functionalized microcapsule (having an encapsulated payload)as illustrated in FIG. 3, according to one embodiment;

FIG. 3 is a chemical reaction diagram showing the preparation of adienophile-functionalized microcapsule (having an encapsulated payload)using the dienophile-functionalized alcohol of FIG. 2, according to oneembodiment;

FIG. 4 is a chemical reaction diagram showing the preparation of apolymeric material with a diene functional group to be chemicallyreacted with a dienophile functional group of thedienophile-functionalized microcapsule of FIG. 3, according to oneembodiment;

FIG. 5 is a flow diagram showing a particular embodiment of a method ofbonding a microcapsule having an encapsulating payload to a polymericmaterial; and

FIG. 6 is a flow diagram showing a particular embodiment of a method ofmodifying a first polymeric material to form a second polymeric materialby replacing a first microcapsule with a second microcapsule.

VI. DETAILED DESCRIPTION

The present disclosure relates to the formation of polymeric materialswith microcapsules (having an encapsulated payload) that are(reversibly) bonded to a polymeric substrate (e.g., a fibrous substrate,such as a cellulosic material). In the present disclosure, a dienophilefunctional group of a dienophile-functionalized microcapsule maychemically react with a diene functional group of a diene-modifiedpolymeric material (e.g., cotton) to bond the microcapsule to thepolymeric material.

As used herein, the term “microcapsule” is used to refer to capsulesthat are in a range of about 10 microns to 1000 microns in diameter.However, it will be appreciated that the following disclosure may beapplied to capsules having a smaller size (also referred to as“nanocapsules”). Further, the present disclosure may apply to naturalpolymeric materials (e.g., cellulosic fibers, such as cotton), syntheticpolymeric materials (e.g., polyester fibers), or a combination thereof(e.g., a cotton/polyester blended fabric). In addition, the presentdisclosure may apply to flexible polymeric materials such as cottonfibers as well as relatively rigid polymeric materials (e.g., athermoplastic, bamboo, etc.), among other alternatives.

In some cases, Diels-Alder chemistry may be used such that themicrocapsule is reversibly bonded to the polymeric material (e.g., via acyclic compound that is formed in a Diels-Alder reaction of an alkenefunctional group with a diene functional group). The reversible natureof the chemical reaction to bond the microcapsule to the polymericmaterial may allow the microcapsule to be removed and “reworked” toregenerate and/or change a payload. Thus, if microcapsules rupture andrelease the encapsulated payload(s) or if there is a desire to modifythe payload(s), the microcapsules can be de-bonded from the polymericmaterial (e.g., via a retro Diels-Alder reaction). Another set ofmicrocapsules (with the same or different payload) may then be(reversibly) bonded to the polymeric material, allowing themicrocapsules to be “reworked” over time without replacing an underlyingpolymeric substrate.

In some implementations, natural polymers containing hydroxyl groups(such as cotton) are modified to incorporate diene functionalities offthe surface. The combination of the dienophile functionalizedmicrocapsules with the diene functionalized cotton allows for covalentbonding and associated adherence of the microcapsules to the cotton.When the combined material is strained, the microcapsules can ruptureand thus release the payload. Using reversible chemistry, the brokenmicrocapsules and/or other microcapsules can easily be reworked toregenerate or change the payload material.

The use of microcapsules allows for a homogenous distribution of thepayload(s). The microcapsules can be incorporated at various volumesdepending on the amount of payload(s) that may be desired. Themicrocapsules can be covalently bonded directly with the polymericfibers. Microcapsules can be generated in a relatively homogenous sizethus allowing for a controlled release of the payload per unit area. Theprotective outer layer of the microcapsule prevents leach out of thepayload, making the microcapsules environmentally friendly.

FIG. 1 is a chemical reaction diagram 100 showing the preparation of apolymeric material with a microcapsule (having an encapsulated payload)that is (reversibly) bonded to a polymeric substrate, according to oneembodiment. FIG. 1 illustrates that a payload may be encapsulated withina polymeric shell of a dienophile-functionalized microcapsule, asdescribed further herein with respect to FIGS. 2 and 3. FIG. 1 furtherillustrates that a polymeric substrate (e.g., a cellulosic material inthe example of FIG. 1) may be modified to include a diene functionalgroup, as described further herein with respect to FIG. 4. In FIG. 1,the microcapsule (including the encapsulated payload) is (reversibly)bonded to the polymeric substrate via a chemical reaction of thedienophile functional group with the diene functional group.

In the example of FIG. 1, the left side of the chemical reaction diagram100 illustrates a dienophile-functionalized microcapsule (having anencapsulated payload) and a diene-functionalized polymeric material. Inthe particular embodiment illustrated in FIG. 1, the polymeric materialincludes a fibrous substrate (e.g., a cellulosic material, such ascotton). The right side of the chemical reaction diagram 100 illustratesthe microcapsule (with the encapsulated payload) bonded to the fibroussubstrate. Thus, FIG. 1 illustrates an example of a (single)microcapsule having the encapsulated payload that is (reversibly) bondedto a polymeric material via a chemical reaction of a dienophilefunctional group with a diene functional group. While FIG. 1 illustratesa single dienophile functional group for a single microcapsule and asingle diene functional group for the polymeric material, it will beappreciated that this is for illustrative purposes only. Asillustrative, non-limiting examples, an available weight percentage ofdiene functionality may be within a range of about 1 to 10 weightpercent of a total weight of a microcapsule, such as within a range ofabout 2 to 8 weight percent, about 3 to 7 weight percent, about 3.5 to 6weight percent, or about 4 to 5 weight percent.

FIG. 1 illustrates that, in some cases, the chemical reaction of thedienophile functional group (of the functionalized microcapsule) withthe diene functional group (of the functionalized polymeric material)may be a reversible reaction to reversibly bond the microcapsule to thepolymeric material. In FIG. 1, the left side of the chemical reactiondiagram 100 and the right side of the chemical reaction diagram 100 areseparated by a forward arrow and a reverse arrow to indicate that thechemical reaction is a reversible reaction. In the particular embodimentillustrated in FIG. 1, a Diels-Alder reaction drives the reaction in aforward direction, and a retro Diels-Alder reaction drives the reactionin a reverse direction.

In the example illustrated in FIG. 1, the microcapsule having theencapsulated payload is reversibly bonded to the polymeric material viaa cyclic compound (e.g., a bicyclic compound). In FIG. 1, the dienophilefunctional group of the dienophile-functionalized microcapsule is analkene functional group (e.g., a cyclic alkene functional group). Thechemical reaction of the alkene functional group with the dienefunctional group (e.g., a cyclic diene functional group) of thediene-functionalized polymeric material forms the bicyclic compound.

As a prophetic example, the microcapsules may be adhered to thepolymeric material (e.g., a cellulosic material in FIG. 1) via covalentbonding using Diels-Alder chemistry. For example, thediene-functionalized polymeric material and thedienophile-functionalized microcapsules may be blended at elevatedtemperatures (e.g., at about 130° C.). As further described herein withrespect to FIG. 2, a furan protected maleic anhydride may bede-protected when heated to a particular temperature (e.g., above about125° C.). In the Diels-Alder chemistry illustrated in FIG. 1, the furanhas been removed as a result of heating. After blending, a temperaturemay be reduced (e.g., to about 70° C.) for a time period of about 2hours in order to allow the forward reaction to occur. The product withadhered microcapsules may be cooled (e.g., to room temperature) andexcess reactants removed.

The right side of the chemical reaction diagram 100 of FIG. 1illustrates that the microcapsule (having the encapsulated payload) isreversibly bonded to the polymeric material via the bicyclic compound.In the example of FIG. 1 in which the dienophile functional group is analkene functional group, the reaction may be reversed via a retroDiels-Alder reaction. FIG. 1 illustrates a prophetic example in whichthe reaction may be reversed by heating (e.g., above about 130° C.) fora particular period of time to reverse the Diels-Alder reaction,allowing the microcapsules to detach from the cellulosic material. Asfurther described herein with respect to FIG. 6, the reversible bondingof the microcapsule to the polymeric material may allow the microcapsulewith the encapsulated payload to be de-bonded from the polymericmaterial (e.g., without the encapsulated payload being released from themicrocapsule).

Thus, FIG. 1 illustrates an example of a polymeric material thatincludes a fibrous substrate (e.g., a cellulosic material) and amicrocapsule (having an encapsulated payload) that is reversibly bondedto the fibrous substrate (e.g., via a cyclic compound). In FIG. 1, themicrocapsule may be bonded to the fibrous substrate via a cycliccompound that is formed as a result of a chemical reaction of adienophile functional group with a diene functional group to form thecyclic compound (e.g., via a Diels-Alder reaction). The dienophilefunctional group is associated with a dienophile-functionalizedmicrocapsule (as described further herein with respect to FIGS. 2 and3), and the diene functional group is associated with adiene-functionalized polymeric material (as described further hereinwith respect to FIG. 4). In the reversible reaction illustrated in FIG.1, the microcapsule may be de-bonded from the polymeric material (e.g.,via a retro Diels-Alder reaction). As described further herein withrespect to FIG. 6, de-bonding the microcapsule may allow for anothermicrocapsule (with the same payload or a different payload) to be bondedto the polymeric substrate.

FIG. 2 is a chemical reaction diagram 200 showing the preparation of adienophile-functionalized alcohol, according to one embodiment. Thedienophile-functionalized alcohol of FIG. 2 may be used to prepare adienophile-functionalized microcapsule (having an encapsulated payload),as illustrated and further described herein with respect to FIG. 3.

In the example illustrated in FIG. 2, an alcohol (e.g., resorcinol) ischemically reacted with an amine (e.g.,3-(Ethoxydimethylsilyl)propylamine) to form an amine-functionalizedalcohol (e.g., amine-functionalized resorcinol). Theamine-functionalized alcohol is chemically reacted with a dienophilematerial (e.g., a furan-protected maleic anhydride) to form adienophile-functionalized alcohol (e.g., resorcinol with a dienophilefunctional group). In the example of FIG. 2, the furan protected maleicanhydride is 3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride. Theprotected maleic anhydride may be de-protected when heated to aparticular temperature, as shown on the left side of the chemicalreaction diagram 100 of FIG. 1.

FIG. 2 illustrates a prophetic example of reaction conditions to formdienophile-functionalized resorcinol. In FIG. 2, theamine-functionalized resorcinol, the furan protected maleic anhydride(3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride), and benzene are heatedat about 80° C. for a time period of about 1 hour. Subsequently, ZnCl₂may be added. After a time period of about 30 minutes,hexamethyldisiloxane (HDMS) may be added, and the reaction may continuefor a time period of about 2 hours.

FIG. 2 illustrates that the chemical reaction of the amine functionalgroup of the amine-functionalized resorcinol with the dienophilematerial (e.g., the furan protected maleic anhydride) results inreplacement of oxygen with nitrogen to form a strained furan. Thus, thedienophile functional group of the dienophile-functionalized resorcinolof FIG. 2 is in protected form. For the Diels-Alder chemistryillustrated in FIG. 1, the furan is removed when heated (e.g., aboveabout 125° C.).

As further described herein with respect to FIG. 3, thedienophile-functionalized alcohol that is formed via the chemicalreactions illustrated in FIG. 2 may be used as a cross-linking agentwhen forming the dienophile-functionalized microcapsule with theencapsulated payload. For example, the dienophile-functionalizedresorcinol may represent a portion of a total amount of resorcinol thatmay be used to form the polymeric shell of the microcapsule. As anillustrative, non-limiting example, the dienophile-functionalizedalcohol may represent between about 10 to 20 weight percent of a totalamount of resorcinol that is used, with a remaining 80 to 90 weightpercent representing non-functionalized resorcinol.

Thus, FIG. 2 illustrates a particular embodiment of a process ofproducing a dienophile-functionalized alcohol (e.g., resorcinol). Thedienophile-functionalized alcohol may represent at least a portion ofthe alcohol that is used during formation of a dienophile-functionalizedmicrocapsule (having an encapsulated payload), as illustrated in FIG. 3.

FIG. 3 is a chemical reaction diagram 300 showing the preparation of adienophile-functionalized microcapsule (having an encapsulated payload),according to one embodiment. In FIG. 3, payload filled microcapsulescontaining dienophile functionality are formed using an oil-in-wateremulsion technique to create a protective polymeric shell around apayload core. The dienophile-functionalized alcohol illustrated in FIG.2 may represent at least a portion of the cross-linking agent that isused to produce the dienophile-functionalized microcapsule of FIG. 3.

In the example of FIG. 3, a payload represents an oil phase that isdispersed into an aqueous continuous phase and stirred to begin anemulsion process. As illustrative, non-limiting examples, the payload(or multiple payloads) may include a perfume oil, a self-healing agent,a disinfectant, a repellant, or a combination thereof. It will beappreciated that various payload(s) may be selected to provide variousfunctionalities for various applications. In FIG. 3, a cross-linkingagent is reacted with a polymeric emulsifying agent to generate acapsule wall around the payload. Particle size may be controlled byadjusting a stir speed during the reaction. For example, a faster stirspeed may result in formation (on average) of smaller (“finer”)particles than a slower stir speed. FIG. 3 further illustrates that acuring stage may be used to complete the reaction between thecross-linking agent and the polymeric emulsifying agent to form themicrocapsules (or nanocapsules, depending on a stir speed).

As illustrated in FIG. 1, the dienophile functional group(s) of thedienophile-functionalized microcapsule of FIG. 3 may chemically reactwith the diene functional group(s) of the diene-functionalized polymericmaterial to (reversibly) bond the microcapsule to the polymericsubstrate.

In a prophetic example, dienophile-functionalized microcapsules may beprepared according to the following process. To a stirring aqueoussolution containing an ethylene maleic anhydride (EMA) copolymersurfactant, urea, NH₄Cl, and resorcinol with a dienophile functionalitymay be added. A pH may be adjusted to about 3.5 by adding NaOH and HCl(or other acids/bases), followed by the addition of an emulsifying agent(e.g., a self-healing agent). The payload may be added with otheringredients, such as monomers and/or pre-polymers, stabilizers,solvents, viscosity modifiers, odorants, colorant/dyes, blowing agents,antioxidants, or co-catalysts, or a combination thereof. Formaldehydemay be added, which acts as a curing agent to complete the shellformation. The resulting microcapsules may be subsequently washed andsieved to remove unreacted material.

Thus, FIG. 3 illustrates a particular embodiment of a process ofproducing a dienophile-functionalized microcapsule (having anencapsulated payload). As illustrated and further described herein withrespect to FIG. 1, a dienophile group of the dienophile-functionalizedmicrocapsule produced according to the process illustrated in FIG. 3 maybe reacted with a diene functional group of a diene-functionalizedpolymeric material to (reversibly) bond the microcapsule to thepolymeric material. FIG. 4 illustrates a particular embodiment of aprocess of functionalizing a polymeric material (e.g., a cellulosicmaterial) to include a diene functional group for reaction with thedienophile functional group.

FIG. 4 is a chemical reaction diagram 400 showing the preparation of adiene-functionalized polymeric substrate to be reacted with thedienophile-functionalized microcapsule formed in FIG. 3. As illustratedand further described herein with respect to FIG. 1, a diene functionalgroup of the diene-functionalized polymeric material produced accordingto the process illustrated in FIG. 4 may be reacted with the dienophilefunctional group of the dienophile-functionalized microcapsule to(reversibly) bond the microcapsule to the polymeric material.

FIG. 4 illustrates a particular example in which a polymeric materialhaving hydroxyl groups may be modified via amine chemistry, followed bya reaction with a diene to generate a polymeric surface with dienefunctionality. An example of a polymeric material with hydroxyl groupsis cotton. Other polymeric material(s) may be selected by those skilledin the art. In the example of FIG. 4, furfuryl isocyanate is an exampleof a material that is used to provide the diene functionality.

FIG. 4 illustrates a prophetic example of reaction conditions associatedwith the preparation of a diene-modified polymeric material (e.g., adiene-modified cellulosic material). In the first chemical reactionshown in FIG. 4, cotton fibers (cellulose) are reacted with an amine(e.g., 3-(Ethoxydimethylsilyl)propylamine) in a solvent (e.g., toluene)at a temperature of about 90° C. for a time period of about 48 hours.After reaction, the product may be rinsed with water to remove residualmaterial. In the second chemical reaction shown in FIG. 4, theamine-functionalized cotton is reacted with furfuryl isocyanate intetrahydrofuran (THF) at a temperature of about 50° C. for a time periodof about 24 hours. The resulting product is diene-modified cottonfibers.

In some cases, the amine functionalization may represent about 4 to 5weight percent of the cellulosic material. In some cases, the weightpercentage may be limited as a result of steric hindrance. It will beappreciated that a degree of amine functionalization may fall within arange of weight percentages, such as in a range of about 2 to 7 weightpercent, in a range of about 3 to 6 weight percent, in a range of about3.5 to about 5.5 weight percent, or in a range of about 4 to about 5weight percent, among other alternative weight percentages.

Thus, FIG. 4 illustrates a particular embodiment of a process offunctionalizing a polymeric material (e.g., a cellulosic material) toinclude a diene functional group for reaction with a dienophilefunctional group of a dienophile-functionalized microcapsule. Asillustrated and further described herein with respect to FIG. 1, themicrocapsule (having the encapsulated payload) may be (reversibly)bonded to the polymeric material via a chemical reaction of the dienefunctional group with the dienophile functional group.

FIG. 5 is a flow diagram of a particular embodiment of a method 500 offorming a polymeric material that includes a microcapsule (having anencapsulated payload) that is bonded to the polymeric material. FIG. 5illustrates an example of a process of producing a microcapsule thatincludes a dienophile functional group (as shown in FIG. 1 and furtherdescribed herein with respect to FIGS. 2 and 3). FIG. 5 also illustratesan example of a process of producing a polymeric material that includesa diene functional group (as shown in FIG. 1 and further describedherein with respect to FIG. 4). FIG. 5 further illustrates that thedienophile-functionalized microcapsule may be applied to thediene-functionalized polymeric material, and the microcapsule may bebonded to the polymeric material via a chemical reaction of thedienophile functional group with the diene functional group.

In the particular embodiment illustrated in FIG. 5, operationsassociated with an example process of producing adienophile-functionalized microcapsule are identified as operations502-506, while operations associated with producing adiene-functionalized polymeric material are illustrated as operations508 and 510. It will be appreciated that the operations shown in FIG. 5are for illustrative purposes only and that the chemical reactions maybe performed in alternative orders, at alternative times, by a singleentity or by multiple entities, or a combination thereof. As an example,one entity (e.g., a specialty chemical manufacturer) may produce thedienophile-functionalized microcapsule, while another entity (e.g., asynthetic fiber manufacturer, a clothing manufacturer, etc.) may producethe diene-functionalized polymeric material. Further, alternative oradditional entities may perform the operations associated with bondingthe microcapsule to the polymeric material via the chemical reaction ofthe dienophile functional group with the diene functional group(illustrated as operations 512 and 514).

The method 500 includes chemically reacting an alcohol with an amine toform an amine-functionalized alcohol, at 502. As an example, in theembodiment illustrated in FIG. 2, an alcohol (e.g., resorcinol) ischemically reacted with an amine (e.g.,3-(Ethoxydimethylsilyl)propylamine) to form an amine-functionalizedalcohol (e.g., resorcinol with an amine functional group).

The method 500 includes chemically reacting the amine-functionalizedalcohol with a dienophile material to form a dienophile-functionalizedalcohol. As an example, in the embodiment illustrated in FIG. 2, theamine-functionalized alcohol (e.g., resorcinol with the amine functionalgroup) is reacted with a dienophile material (e.g., a furan-protectedmaleic anhydride, such as 3,6-epoxy-1,2,3,6-tetrahydrophthalicanhydride) to form a dienophile-functionalized alcohol (e.g., resorcinolwith a dienophile functional group).

The method 500 includes using the dienophile-functionalized alcohol toform a microcapsule (having an encapsulated payload) that includes adienophile functional group, at 506. For example, thedienophile-functionalized alcohol formed in the embodiment illustratedin FIG. 2 (e.g., resorcinol with the dienophile functional group) mayrepresent at least a portion of resorcinol that is used to form thedienophile-functionalized microcapsule illustrated in FIG. 3. As anillustrative, non-limiting example, the dienophile-functionalizedresorcinol may represent about 10 to 20 weight percent of a total weightof resorcinol, while non-functionalized resorcinol may represent about80 to 90 weight percent.

The method 500 includes chemically reacting a fibrous material (thatincludes a hydroxyl group) with an amine to form an amine-functionalizedfibrous material, at 508. As an example, in the embodiment illustratedin FIG. 4, the cellulosic material (with two hydroxyl groups shown forillustrative purposes only) is reacted with an amine (e.g.,3-(Ethoxydimethylsilyl)propylamine) to form the amine-functionalizedcellulosic material. FIG. 4 further illustrates that a portion of thehydroxyl groups of the cellulosic material may remain unreacted (e.g.,as a result of steric hindrance). In some cases, the aminefunctionalization may represent about 4 to 5 weight percent of thecellulosic material.

The method 500 includes chemically reacting the amine-functionalizedfibrous material with a diene to form a polymeric material that includesa diene functional group, at 510. As an example, in the embodimentillustrated in FIG. 4, the amine-functionalized cellulosic material isreacted with a diene (e.g., furfuryl isocyanate) to form thediene-functionalized cellulosic material.

The method 500 includes applying the microcapsule (having theencapsulated payload) that includes the dienophile-functional group tothe polymeric material that includes the diene functional group, at 512.For example, referring to FIG. 1, the dienophile-functionalizedmicrocapsule with the encapsulated payload may be applied to thediene-functionalized polymeric material (e.g., cellulosic material).

The method 500 further includes (reversibly) bonding the microcapsule(having the encapsulated payload to the polymeric material via achemical reaction of the dienophile functional group with the dienefunctional group (e.g., via a Diels-Alder reaction), at 514. Forexample, referring to FIG. 1, the microcapsule with the encapsulatedpayload may be (reversibly) bonded to the polymeric material via acyclic compound that is formed as a result of a chemical reaction of thealkene functional group of the microcapsule with the diene functionalgroup of the cellulosic material (e.g., via a Diels-Alder reaction). Inthe particular embodiment illustrated in FIG. 1, the alkene functionalgroup is a cyclic alkene functional group, the diene functional group isa cyclic diene functional group, and the cyclic compound is a bicycliccompound.

While not shown in the example of FIG. 5, in some cases, themicrocapsule may be de-bonded from the polymeric material via a retroDiels-Alder reaction. As further described herein with respect to FIG.6, reversibly bonding the microcapsule to a polymeric material may allowthe microcapsule to be removed and replaced with another microcapsule(that may contain the same payload or a different payload).

Thus, FIG. 5 illustrates various operations associated with bonding amicrocapsule (having an encapsulated payload) to a polymeric material.In some cases, the same entity or multiple entities may perform one ormore of the operations. As an example, one or more entities (e.g., oneor more specialty chemical manufacturers) may perform the operations502-506 to form the dienophile-functionalized microcapsule (having theencapsulated payload). Another entity (or entities) or the same entity(or entities) may perform the operations 508 and 510 to form thediene-functionalized polymeric material. As a further example, anotherentity (or entities) or the same entity (or entities) may perform theoperations 512 and 514 to (reversibly) bond the microcapsule to thepolymeric material.

FIG. 6 is a flow diagram of a particular embodiment of a method 600 ofmodifying a first polymeric material by replacing a first microcapsule(e.g., having a first encapsulated payload) that is reversibly bonded tothe first polymeric material with a second microcapsule (having a secondencapsulated payload) to form a second polymeric material.

The method 600 includes de-bonding a first microcapsule (e.g., includinga first encapsulated payload) that is reversibly bonded to a polymericsubstrate of a first polymeric material to form a diene-functionalizedpolymeric substrate, at 602. As an example, referring to FIG. 1, a retroDiels-Alder reaction may de-bond the first microcapsule from thepolymeric material (e.g., a cellulosic material). In the example of FIG.1, the first microcapsule is reversibly bonded to the polymericsubstrate via a first cyclic compound (e.g., a bicyclic compound). Insome cases, the first microcapsule may be de-bonded without a firstencapsulated payload of the first microcapsule being released from themicrocapsule.

The method 600 includes applying a second microcapsule (having a secondencapsulated payload) that includes a dienophile functional group to thediene-functionalized polymeric substrate, at 604. In some cases, thefirst encapsulated payload may be different from the second encapsulatedpayload. In other cases, the first encapsulated payload may be the sameas the second encapsulated payload. As an illustrative example, a firstencapsulated payload may be released as a result of a microcapsule beingruptured. To illustrate, application of a threshold amount of mechanicalstrain to a fibrous material may result in release of the firstencapsulated payload from the first microcapsule. In this case, thesecond microcapsule may allow for replacement of the payload that wasreleased without modification to a polymeric substrate (e.g., cottonfibers). As another example, it may be desirable to replace/change anencapsulated payload in some cases. To illustrate, an entity (e.g., amanufacturer, an end user, etc.) may desire to replace a first perfumeoil with a second perfume oil. In this case, the second microcapsule mayallow the entity to change perfume oils without modification to thepolymeric substrate (e.g., cotton fibers).

The method 600 further includes forming a second polymeric material viaa chemical reaction of a dienophile functional group (of the secondmicrocapsule) with a diene functional group (of thedienophile-functionalized polymeric substrate), at 606. The secondmicrocapsule (having the second encapsulated payload) is bonded to thepolymeric substrate via the chemical reaction of the dienophilefunctional group with the diene functional group. In some cases, thesecond microcapsule having the second encapsulated payload is reversiblybonded to the polymeric substrate via a second cyclic compound (e.g., abicyclic compound) that is formed as a result of the chemical reactionof the dienophile functional group and the diene functional group of thediene-functionalized polymeric substrate.

Thus, FIG. 6 illustrates that the ability to de-bond (e.g., via a retroDiels-Alder reaction) a first microcapsule (that may have a firstencapsulated payload) that is reversibly bonded to a polymeric substrateof a first polymeric material may allow for formation of a secondpolymeric material. After de-bonding the first microcapsule, a secondmicrocapsule with a second encapsulated payload may be chemically bondedto the polymeric substrate. In some cases, the second encapsulatedpayload may be the same as the first encapsulated payload in order toreplace a payload that is released as a result of the first microcapsulebeing ruptured. In other cases, the second encapsulated payload may be adifferent payload in order to provide alternative functionality when amicrocapsule is ruptured.

The previous description of the disclosed embodiments is provided toenable any person skilled in the art to make or use the disclosedembodiments. Various modifications to these embodiments will be readilyapparent to those skilled in the art, and the generic principles definedherein may be applied to other embodiments without departing from thescope of the disclosure. Thus, the present disclosure is not intended tobe limited to the embodiments shown herein but is to be accorded thewidest scope possible consistent with the principles and features asdefined by the following claims.

1. A polymeric material comprising: a fibrous substrate; a cycliccompound chemically bonded to the fibrous substrate; and a microcapsulehaving a shell encapsulating a payload, wherein the shell is reversiblybonded to the fibrous substrate via the cyclic compound.
 2. Thepolymeric material of claim 1, wherein the fibrous substrate includes acellulosic material.
 3. The polymeric material of claim 2, wherein thecellulosic material is cotton.
 4. The polymeric material of claim 1,wherein the cyclic compound is a bicyclic compound.
 5. The polymericmaterial of claim 4, wherein the bicyclic compound is formed via achemical reaction of a cyclic alkene functional group and a cyclic dienefunctional group.
 6. The polymeric material of claim 1, whereinapplication of mechanical strain sufficient to rupture the microcapsuleresults in release of the encapsulated payload from the microcapsule. 7.The polymeric material of claim 1, wherein the encapsulated payloadincludes a perfume oil, a self-healing agent, a disinfectant, or arepellant.
 8. The polymeric material of claim 1, wherein themicrocapsule has a characteristic dimension in a range of about 10microns to about 1000 microns.